Summary statistics for outcome measures, network measures and county level control variables
| Variable | Mean | Std. dev. | Observations |
| Outcome measures | |||
| COVID-19 mortality rate—population level | 34.76 | 46.13 | 3120 |
| COVID-19 mortality rate—case level | 2121.57 | 2414.12 | 3203 |
| COVID-19 positive case rate | 1496.86 | 1298.21 | 3120 |
| Network measures | |||
| Number of nodes* | 3292.45 | 2893.42 | 2806 |
| Number of links* | 154 797.99 | 152 230.05 | 2806 |
| PCP/nonPCP degree centrality ratio | 1.7 | 4.3 | 2582 |
| Betweenness centralisation | 0.01 | 0.05 | 2549 |
| Eigenvector centralisation | 0.22 | 0.15 | 2549 |
| County level controls | |||
| Mean household income | 32 870 | 6979.48 | 3131 |
| Unemployment rate | 0.05 | 0.02 | 3131 |
| Diabetes prevalence | 0.12 | 0.04 | 3142 |
| % 65 and older | 0.19 | 0.05 | 3142 |
| % females | 0.5 | 0.02 | 3142 |
| % non-Hispanic black | 0.09 | 0.14 | 3142 |
*Numbers based on county averages from hospital referral region networks.
non-PCP, non-primary care provider; PCP, primary care provider.